Can I Drink Water with Low Sodium? Understanding Hyponatremia Risks

November 13, 2025 •

4 min read

According to the World Health Organization, the global mean intake of sodium for adults is more than double the recommended amount. While many focus on reducing excess sodium from food, a lesser-known concern is drinking too much water without adequate sodium, which can lead to a dangerous condition called hyponatremia. So, can I drink water with low sodium?

Quick Summary

Drinking water with low sodium is generally safe, but excessive intake can dilute blood sodium, causing hyponatremia. The main risk comes from overhydration, not the water's low sodium content itself, especially for endurance athletes or people with specific medical conditions.

Key Points

Low sodium water is safe for most: The sodium content in normal tap or bottled water is too low to be a health risk for the average person.
Hyponatremia is the real danger: Low blood sodium levels (hyponatremia) typically result from overconsuming plain water, which dilutes electrolytes, not from drinking water that naturally contains low sodium.
Endurance athletes are at higher risk: Individuals engaged in long, intense exercise lose sodium through sweat and must replenish electrolytes, not just plain water, to avoid hyponatremia.
Symptoms include headache and confusion: Mild hyponatremia can cause nausea and headaches, while severe cases can lead to confusion, seizures, or coma.
Consult a doctor for medical conditions: People with pre-existing conditions like heart or kidney disease, or those on certain medications, should consult a doctor about their fluid and sodium intake.
Increase sodium naturally if needed: For medically low sodium, consuming foods like broth, soups, and vegetable juices under a doctor's supervision can help restore levels.

The Surprising Truth About Water and Sodium Balance

For most healthy people, the sodium content of drinking water is not a major concern. Tap water and most bottled waters contain very little sodium compared to the amount we get from food. The real danger arises from overconsumption of fluids, a condition sometimes called water intoxication, which can dilute the body's sodium levels and lead to hyponatremia. This is particularly relevant for endurance athletes, older adults, and individuals with certain medical conditions.

What is Hyponatremia?

Hyponatremia is a condition where the sodium concentration in the blood is abnormally low, dropping below 135 mEq/L. Sodium is a crucial electrolyte that helps regulate fluid balance and is vital for nerve and muscle function. When blood sodium levels fall too low, extra water moves into your cells, causing them to swell. This can be especially dangerous in the brain, where it can cause neurological symptoms, seizures, or, in severe cases, coma.

Symptoms of hyponatremia range from mild to severe, and they can mimic other conditions like heatstroke. Mild symptoms often include nausea, headaches, fatigue, and muscle cramps. Severe symptoms can lead to disorientation, seizures, and unconsciousness.

Who is at Risk?

While the average person is not at risk from drinking normal amounts of water, certain groups must be more mindful of their fluid and sodium intake:

Endurance Athletes: Marathon runners, triathletes, and others who engage in prolonged, intense exercise lose sodium through sweat. If they replace fluids only with plain water and do not consume electrolytes, they can develop exercise-associated hyponatremia.
Older Adults: Age-related changes, certain medications (like diuretics), and a higher likelihood of chronic diseases can increase the risk of hyponatremia in older adults.
Individuals with Underlying Conditions: Congestive heart failure, kidney disease, liver disease, and the syndrome of inappropriate anti-diuretic hormone (SIADH) can all affect the body's ability to excrete water, leading to diluted sodium levels.

The Role of Water Sources

Different water sources have varying sodium levels, but for most people, the difference is negligible. The following comparison table highlights typical sodium content:


Water Type	Typical Sodium Content	Consideration for Consumption
Tap Water	18-41 mg/L	Safe for most people. Sodium is a tiny fraction of total intake.
Bottled Water	4-8 mg/L	Often has very low sodium. A good choice for those on very strict low-sodium diets.
Softened Water	Can be higher	Ion exchange water softeners replace hard minerals with sodium. Should be monitored by those on restricted diets.
Sports Drinks	Variable, higher than water	Contains electrolytes like sodium to help replace what is lost during intense exercise.

For those on medically restricted diets, water with less than 20 mg/L of sodium is generally recommended, and testing your water can provide certainty.

How to Maintain Healthy Sodium and Fluid Levels

Instead of worrying about the specific sodium content of your water, focus on balanced hydration and overall sodium intake, which primarily comes from food. Here are some key strategies:

Listen to Your Body's Thirst Cues: Drink when you feel thirsty. Your body has a natural mechanism to tell you when it needs fluids.
Balance Water with Electrolytes During Exercise: For prolonged workouts, alternate between plain water and a sports drink or consume electrolyte-rich foods to replenish lost sodium.
Be Mindful of High-Sodium Foods: Processed and packaged foods are a major source of dietary sodium. Reducing these foods and cooking from scratch can help manage your intake.
Increase Natural Sodium Sources if Needed: For those with medically low sodium levels, naturally sodium-rich foods like broths, soups, and vegetable juices can help restore balance under a doctor's guidance.
Consult a Healthcare Professional: If you have concerns about your sodium levels, especially if you have a pre-existing medical condition, speak to a doctor or registered dietitian.

Conclusion

For the vast majority of healthy people, the answer to the question "can I drink water with low sodium?" is a resounding yes. The amount of sodium in most drinking water is insignificant compared to dietary intake. The primary risk of low blood sodium (hyponatremia) is from overconsumption of fluids, especially during prolonged physical activity. By paying attention to your body's signals, balancing fluid intake with electrolytes during exercise, and managing overall dietary sodium, you can maintain a healthy and safe hydration routine. For those with specific medical conditions, consulting a healthcare provider is the best course of action to ensure proper electrolyte balance.

Natural Sources of Sodium

When a person is advised to increase their sodium intake, focusing on natural food sources is often the best approach. This helps avoid excessive intake from highly processed foods. Examples include:

Cottage cheese: A good source of protein and sodium.
Broth and soups: Especially flavorful and hydrating options.
Pickles: Fermented foods can be a source of sodium and beneficial bacteria.
Seafood: Naturally contains sodium and other minerals.
Salted nuts: A convenient snack for a sodium boost.
Vegetable juice: Options like V8 juice are higher in sodium.

The Importance of Balanced Hydration

Striking a balance is key. While avoiding too much sodium is important for cardiovascular health, restricting it too severely can also have consequences. The average North American consumes far more than the recommended daily sodium intake, so for most, focusing on a lower sodium diet is prudent. However, the fear of low-sodium water is largely unfounded for the healthy population. The risks associated with hyponatremia are primarily linked to medical conditions or extreme overhydration, not the negligible amount of sodium in your average glass of water.

For more detailed information on healthy sodium levels, consult guidelines from organizations like the World Health Organization.

Frequently Asked Questions

For most healthy individuals, drinking water with low sodium is not harmful. The risk of low blood sodium (hyponatremia) typically comes from drinking excessive amounts of plain water, which dilutes the sodium already in your body, rather than from the low-sodium content of the water itself.

There is no single amount considered "too much" for everyone, as it depends on factors like activity level, climate, and health. However, drinking a significantly large volume of water in a short period can overwhelm the kidneys' ability to excrete fluid, especially if you're not also replenishing electrolytes.

Early symptoms of hyponatremia can include nausea, headache, fatigue, and muscle cramps. It is important to pay attention to these signs, especially during or after intense exercise.

For prolonged, intense exercise, it is recommended that athletes balance plain water with sports drinks containing electrolytes, including sodium, to replace what is lost through sweat. This helps prevent exercise-associated hyponatremia.

You can naturally increase sodium levels by consuming more sodium-rich foods like broth, soups, salted nuts, and certain dairy products like cottage cheese. However, this should only be done if medically necessary and under a doctor's guidance.

Yes. Water softeners use an ion exchange process that replaces hard minerals with sodium. This can increase the sodium content of your drinking water and is a concern for people on medically restricted low-sodium diets.

While recommendations vary, for most adults, a healthy intake is between 1,500mg and 2,300mg of sodium per day. The minimum daily requirement is about 500mg, but many people in developed countries consume much more, primarily from processed foods.

You should seek emergency medical care for anyone who develops severe symptoms of hyponatremia, such as confusion, seizures, or loss of consciousness. For milder symptoms or concerns about risk factors, call your healthcare professional for advice.